Automotive body parts may be joined by spot welding operations. The assembly line in an automotive body shop has a series of stations in which welding operations are performed by robots or by human operators. The selection or design of a weld gun capable of performing a specified weld operation (i.e. a sequence of weld points) is one step in process planning and tool/equipment design in an automotive body shop. Typically, the process includes assigning welds to each weld operation and commencing steps to identify an existing weld gun that is capable of performing the operation. This involves validating both geometric (i.e. interference) constraints and weld processing constraints (e.g. welding current).
Weld guns may be selected based on weld process requirements and constraints (weld force, current and cycle time requirements) and weld gun accessibility constraints (size and shape of the weld gun). The processing and accessibility constraints of a weld gun depend on different modules of the weld gun. Basically, spot welding guns comprise different modules such as actuator modules, chassis modules, arm modules, power supply modules and dress package modules. These main modules further comprise a plurality of sub modules. For example, each arm module is an assembly of arms, holders, adapters and electrode caps. Each module has different parameters based on its suppliers, materials, manufacturing process, technology and size/shape. For example, an actuator can be air or servo type with different force ratings. The throat area of the weld gun may depend on the shape and size of the arm modules.
Identifying candidate weld guns from a potentially large library of existing weld gun designs is known to be a manual process aided by commercial software tools. Commercial software provide tools to assist the engineer to select suitable weld guns, however this process still involves a number of steps that are manual, error-prone, and incomplete.